Measuring Palpebral Fissure Height in Real Time for Personalizing Airflow within Ora’s Controlled Adverse Environment 2.0

Abstract

Purpose : Airflow during the Ora Controlled Adverse Environment (CAE) is a critical variable in inducing and enhancing signs and symptoms in dry eye. Instead of a static level of airflow we aim to use an adjustable airflow to be able to titrate the amount of air delivered to each subject’s sensitivity as measured by changes in palpebral fissure height. Narrowing of the palpebral fissure is a physiological safety mechanism to protect the eye against the environmental changes and aid in prevention of increased signs and symptoms associated with dry eye.

Methods : Each subject was seated in the CAE 2.0 with customizable airflow delivered to each patient’s eye. A machine learning 3 lens camera with custom AI was used to measure distance from the camera to the eye allowing for calculation in mm of palpebral fissure height. Utilizing YOLO object detection models, we identified the palpebral fissure height for each subject in real time and averaged the values between the two eyes. A baseline measurement of palpebral fissure height is measured over a 30 second period prior to the start of airflow. Airflow was increased incrementally until the palpebral fissure height narrowed by the same percentage for all subjects. Airflow increases from 1.3 cubic feet per minute (CFM) up to the maximum airflow output of the system over a 10-minute period.

Results : Four patients were evaluated in the CAE 2.0 on three consecutive visits. Baseline palpebral fissure heights ranged from 8.97mm to 12.12mm. Mean titration airflow was 5.1 CFM and mean time to titration was 6 minutes 5 seconds. In 3 subjects, the standard deviation was <0.5 CFM suggesting good reproducibility of titration. One subject showed poor agreement in titration with a standard deviation of 1.44.

Conclusions : Palpebral fissure height narrowing with increased airflow shows promise in being consistent and reproducible. Measuring palpebral fissure height is an important indicator to a patient’s physiologic response and may vary based on ocular surface sensitivity and response to environment. This research showcased that titrating airflow in the Ora CAE 2.0 optimized to the individual may enhance expression of dry eye signs and symptoms.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.